At Last I Have A Dowty (photos may not be visible to none regisitered members)

[alastair_vns]

Have you had a look on ebay possibly get one there, its amazing how expensive small parts like bearings cost.

[BN]

[alastair_vns]

Have you tried your local diy and auto shops?

[BN]

[BN]

The going is getting really tough now 
I have the rear engine bearer out and have undone the loads of brass nuts for the casing of the jet (some were steel - uhh)  , but then it gets really difficult 

The studs are solid in the jet housing and the adhesive sealant is not helping by holding the casing in solid 

Time for a cup of tea and think right now. If that was not enough  ,  there is a torn oil seal deep in the housing and it has to come out.

Losing my sense of humour right now 

[flat broke]

So are these studs or are they through bolted from the other side?  I don't want to offer advice that may make things worse for you.

[BN]

So are these studs or are they through bolted from the other side?  I don't want to offer advice that may make things worse for you.

The studs 'appear' to be welded to the galvanised intake grill and that is offered up from the underneath, through the hull and through the jet housing. The jet housing is additionally sealed with some sort of sealant to the hull. Even if I could get the bolts free, I will still have to prise the jet unit from the hull and its sealant. At the moment I am considering leaving the unit in, but I need to remove the bearing housing which is equally stuck.

The idea was to remove the big housing and bore out the bearing housing, see diagram and make a new bearing housing. Just need to sit down with a coffee and think about this one.

[BN]

Urika    I have done it.
It is amassing what a cup of tea and a bit of chocolate can do  
Having thought about the removal of this impossible item, I was getting a bit depressed    so deep thought was required and yes it came out. In picture 1, you will see the seam, but could I budge it, no, so patience and care and a lot of heat to the point that if I cracked the main housing, it really would not have mattered, because it was stuck and the unit would be irreparable.

However, it moved and thousands of an inch by thousands of an inch it came out after 2 hours. The withdrawal threads, stripped, but I cut down a nut and put it behind the hole for extraction. These units are so precise that when the bearing housing is removed, it marks the casing, so they place solder (see picture 3) in pre drilled holes to check that it has or has not been moved, just like aircraft engineering. Look at the gunk in the inner housing 

I am so pleased, I can now continue with easier jobs  

[flat broke]

Well done!! You can now write a manual on ALL the problems one may encounter while stripping on of these units.

Does this mean the jet housing can stay put?

[BN]

It most certainly does   and I am just ordering 25 x 5/16 BSW brass nuts to replace the old ones, together with stainless washers and split rings  

As for writing the manual, it is an idea, but the job is one of the most worrying I have done because there are no settings, so it will be educated guess work to reassemble, but that is some time away yet.

Need to clean everything up and prepare it now. The engine still has to come out and be rebuilt, then a respray of the hull, engine and new screen, seats and cleats etc. The fuel tank is brass. The quality of build of these boats is astounding, it is pure aircraft build. Did you see the soldered holes to show that the bearing housing had not been removed, so this is the first time in 51 years, not bad.

[flat broke]

Over the years I have built up a good rapport with the local bearing supplier.  They are used to me coming in with an oddball bearing and are great at matching size or bearing number. If you have not already done so, it may be worth gathering up all your bearings and going directly to the local wholesale/retail outfit.  I find working face to face as opposed to over the phone or the computer works best.

[BN]

[BN]

I have just discovered that the main housing for the jet unit is fixed to the hull via a plate that was embedded into the hull at manufacture. Should it require removal, that is a major problem, even for a broken stud, which would have been welded to the footing plate 

[BN]

More shocks, the bearing bush is made from Titanium. That will not be made in the same material for sure, aircraft quality aluminium will be used or stainless steel.

[flat broke]

Also when refitting the bearings in aluminium. Heat the housing in the oven until it just starts to hiss when you spit on it.  Chill the bearing in the freezer.  Drop the bearing in no problem. No half measures or the bearing gets warm before it seats fully.

BTW you might wait until your significant other is out for a while before you start baking boat bits in the oven!